For the "simple" case, looking ONLY for IDENTICAL curves, compare endpoints and (as required for curve type) center or knot or whatever points.
For the more difficult case where curves partially overlap...you need to do more math.
Are these all "dumb" curves, NOT used for anything else?
Or are these curves used for other features (extrude/revolve/etc.)? if this is the case, it will be more difficult to deal with.
Production: NX10.0.3.5 MP5 + patch/TC11.2
I'd rather be e-steemed than e-diseaseled